Method and apparatus for wet spinning of artificial filaments



Jan. 2, 1951 2,536,092 Y l. S. ROBERTS METHOD AND APPARATUS FOR WET SPINNING 0F ARTIFICIAL FILAMENTS Filed Sept. 21, 1946 INVENTOR. //VGHAM 6. ROBERTS BY-lj Patented Jan. 2, 1951 UNITED STATES PATENT, omen Ingham S. Roberts, Ridley Park, Pa., assignor to American Viscose Corporation, Wilmington, 'DeL, a corporation of Delaware Application September 21, 1946, Serial no; 698,431

1 It has heretofore been suggested to improve spinning conditions immediatly around the spinneret by directing the coagulating liquid to flow around the spinneret so that it flows generally in the same direction as the filaments as they'leave the spinneret. It has been found, however, that when spinning under these conditions at high velocities, air or gas tends to settle out on, and remain in contact with, the face of the spinneret in the coagulating liquid. 'Such air or gas may be derived from that dissolved in the coagulating liquid or spinning'material as it is'supplied to the spinning station or it "may result from the reaction occurring upon contact of the spinning materialwith the coagulating liquid, such as viscose with aqueous sulfuric acid; The accumulation of gas may be local or general over the spinneret face and results in irregular filament quality' and/or filament breakage right at the spinneret.

Unexpectedly it has now been found that spinning'can be greatly improved by directlya stream of the coagulating liquid under viscous flow conditions (1. e., non-turbulent conditions) across the face of the spinneret so that the liquid inimmediate proximity to all orifice-containing areas in the spinneret face is forced to move at a substantial velocity transversely of the bores of the orifices, thereby sweeping. past the filament-forming material even as it is first extruded from the orifices.

As illustrated in the. accompanying drawing, various embodiments may be employed for effecting my invention.

Figure 1 is an elevation partly in section, of one embodiment for executing the invention,

Figure 2 is a similar elevation, partly in section, illustrating a modification,

Figure 3 is a section .takeno'n line III-III of Figure 2,

' Figure-4 is a horizontal section through a modiflcation,

Figure 5 isa section on line VV of Figure 4, illustrating, the position occupied by the device of Figure 4 in the spinningbath, g Figureo is a section. on line VI''VI of Figure 5,'and I j Figure? is a section through still another embodiment.

In Figure I there is shown a coagulatingbath 2, a spinneret 3 within the coagulating bath, a supply pipe I for delivering spinning material to the spinneret; andxmeans comprising a conduit 5 for delivering: a:coagulatingliquid to. the container 6. As shown, the spinuerett has a plu Y 14 Claims. (01. 18-8') rallty oflorifices, 1 in its face a and the conduit '5 has a" discharge opening 9 so arranged thata stream of coagulating liquid is directed transversely of the face 8 of the spinneret. The

- streams of filament-forming material discharged streams substantially. immediately after they i leave the orifices thereby assuringcontact of the spinning :material rightafter issuance from the spinneret "with a" coagulating liquid of substam;

tially full concentration and full temperature". The coagulating liquiddischargedfrom conduit 5 passes transversely of the spinneret face in direc't contact therewith so that there is no opportunity for air or other gas to settle out and accumulate upon the face of the spinneret. This assures that there will be no disruption of the filament-forming streams at the spinneret faceby virtue of the development of gas bubbles. Since the coagulating liquid passes across the entire spinneret face before it is allowed to mingle with the general body of liquid in the container 6, substantially the full concentration of the effective element orelements in such liquid acts upon-the entire group of filaments regardless of the'rel'a tive position of such filaments in the spinneret The coagulating liquid in the-stream passing over thespinneret face not only remains at" face.

substantially its full effective concentration throughout its passage across'the spinneret face, but it also accumulates a practically negligible amount of contaminating decomposition prod' ucts as it passesalong the face since in such pas sage it makes contact with but a restricted length of the filaments.

As the filaments'leave the region in front of the spinneret face where they pass through the transverse: stream ofthe-"coagulating medium,

they enter into the general body of the coagulat ingbath where further setting up occurs." As they pass through the general body of the coague lating bath; the portion of the bath in immediate; proximity to the filaments-tends to move in thesame-"direction asaresult of the dragging-action of the filaments thereoni "The filaments may pass from the coagulating bath around guide" l0 upward to a g'ddet or other drawing wheel or device.

. The embodiment of Figures 2 and 3 illustrates a 'modificatioi in which. the "stream' of coagu1at-.

assingover the face of the Spinneret isldeflec led-such as byian arcuate' -deflector H, which may-be'supportedby a bracket 1-2 se ing liquid-aft cured to a ring l3 which fits about the upper end of the conduit 5. Inthis embodiment, the deflector ll prevents the coagulating liquid stream from Welling up at the surface of the coagulating bath above the spinneret. tv also tends to cause the coagulating liquid to flow generally in the direction of travel of the filaments in th up per zone of the coagulating bath comprising the region through which the filaments pass on their way to the guide It.

While Figures 1 to 3 show ahorizontal spinning arrangement in which the spinneret face is disposed approximately in a vertical plane, the face may be disposed in a horizontal plane and then spinning either downwardly .or upwardly within a coagulatingbath, or the face may be disposed at any angle to a horizontal or vertical plane.

In Figures 4 to 6 there is disclosed an embodiment which, besides controlling the temperature and composition of the coagulating liquid supplied to the spinneret, also provides for an extremely eflicient utilization of the coagulating mediumfor maintaining it as a relatively narrow confined stream flowing in the direction of the filaments so that the liqu'id'after passing transversely of the spinneret does not have the oppor tunity (as in the embodiments'of Figures 1 to 3) to intermingle with a relatively dilute and diffen ent-temperatured liquid medium before contacting the filaments as they leaye the region near the spinneret. This system is 'efiicient not only in the amount of liquid required to contact eachof the filaments, depending upon the qualities desired in the final product. For most purposes demanding both a high strength and a high extensibility, it is preferred to minimize the extent of bath drag upon the filaments which may be done by imparting to the coagulating liquid passing through the discharge channel a velocity substantially the same as that of the filaments or somewhatgreater. By the present invention, it is possible to spin the filaments at extremey high speeds, such as 180 to 200 or more meters per minute while avoiding excessive bath drag.

The attachment comprises a block l4 containing a lateral recess l5. There are also provided two approximately aligned bores f6 and I'l .which communicate with the recess l5. A threaded extension I8 projects concentrically with the bore l1 and is provided with a recess l9 adapted to receive a spinneret coupling 20 So that a spinneret 2| projects through the borel'l. A union 22 engages the thread on the extension l8 and retains the spinneret assembly in place.

'The bore i6 has an enlarged portion toward the outside of the block which is adapted to receive a conduit system 23 for discharging filaments and coagulating liquid from the assembly. While this conduit system may comprise a single long tube fitted within the large portion-of bore "5, a preferred form is shown in which a g ass tube 24 is seated within the bore and held in place by a protecting sleeve 25 of hard resin such as Bakelite, hard rubber, vinyl resin, polystyrene, Lucite, or the like. The glass sleeve may be replaced by porcelain or other wear and corrosionresistant material which does not exert abrasive action upon the filaments. As shown, the sleeve 25 may extend only part of the full length of the central tube 24, but if desired, it may extend the full length of the tube 24.

A bore 26 is provided to receive a coupling to any suitable conduit fOr supplying the coagulating liquid to the attachment. The bore 26 communicates with a passage 2'! which communicates with the recess l5 adjacent the spinneret 2i. Bore 21 is preferably curved gradually to minimize turbulence as the stream of liquid passes through it. Within recess I5 there is provided a plug 28 having an enlarged end 29 adapted to be seated against a gasket 38 placed around the open end of the recess IS. The plug 23 is secured in position by means of a screw clamp comprising a strap 3| hinged upon the block M at 32 and pivotally connected to a link- 32' provided with an inclined faced groove v3t adapted to dovetail with a corresponding face ofa groove34 in a projecting lug 35 upon the block 14. the link 32' and bears against the plug 28.

The plug is provided with'a groove 3'! which is in alignment with the bores 16 and H in the block l4 and has a lateral extension 31a communicating with the passage 21 in.block M. As shown, the groove 31, when plug 28 is fitted within the recess. i5, provides a small chamber with one end thereof in proximity to the spinneret face. to deflect as non-turbulentl'y as possible the co-v agulating liquid which passes beyond the spinneret face from the passage 21. As shown particularly in both Figures 4 and 5, this chamber gradually diminishes in cross-section with its distance from the spinneret face sothat it merges gradually with the bore 16. Preferably, the crosssection inside tube 24 is less than that of paS-. sage 21 and the intermediate chambers 31a and Lucite, methyl methacrylate resins, etc., to allow observation of the spinning performance.

As shown, it will be observed that the coagulat ing liquid proceeds through the passage 21 transversely across the face of the spinneret 2! and is then deflected so that it passes through the channel comprising the bore i5 and the tube 24 in substantial alignment with the spinneret. This confinin'r of the coagulating liquid in a relatively.

narrow channel as it proceeds to and from the spinneret assures the most eflicient use of the liquid. avoids accumulation of gas upon the spin neret face with resultant breakage of filaments, provides for contact of all of the filamentform-- ing streams immediately after emergence from the spinneret orifices with coagulating liquid of full strength and at the, proper temperature' whether this be above or below normal room tent-I,

In addition, thecoagulating liquid in contact with the filaments as they proceed from};

perature.

A screw 36 threadedlyengages a bore in The lateral wall of this chamber is curved.

the-transverse 'zone inv front of. the spinneretcface is; ofrelatlvely highstrengthnbecause it is preventedfrom mingling with comparativelyspent coagulatingliquid-such aswould be present if the conduit system 23 were eliminated.

,Figure 7 illustrates a, modification in :which a conduit dllfor supplying coagulating liquid is disp0sed;centrally of the face. of aspinneret M. The; effective area of the face, of the spinneret is annularandcontains a plurality of rows of orifices 42. A conduit i3 supplies spinning material to the-chamber within the spinneret in. customary fashion, a gasket 44 being provided between conduit to and the inside flange 45 of the spinneret-.,- A deflecting knob 46 is... carried upon .a bracket comprising severalspring legs 41. adapted to. be forccdiinto the bore of conduit til. In this arrangement,- the. coagulating. liquid proceeds transversely of the spinneret face fromits center as ;a,-radiating sheetand after leaving the zone adjacent the spinneret,- the filaments-procee through the general bath in the receptacle 45 about a guide 59 and then: upwardly out of the bath to a suitable withdrawing godet or the'l-ike.

It is to;be understood that the specific embodiments shown are illustrative. only and that changesand variations may be made without de parting from the spirit and scope of the inven tion as-defined in the appended;claims.

-I.-claim:

. l'., The method of spinning artificial filaments comprising the steps oiiorcing a stream of coagulating liquid to fiow at a substantial velocity under-conditions of viscous flow transversely of the entire face of a spinneretandextruding the filament-forming material through orifices in the spinneret face directly into the stream substantially. at right angles to the general direc tion of the stream, then deflecting therentire bodyj of. the liquid coagulating stream into a straight. channel in approximate alignment with the-spinneret orifices and passing-the filaments through the deflected stream at a controlled velocity relative to that of thestream.

v 2;"Thezmethod of spinning artificial filaments comprising the steps of forcing a stream of coagulating liquid to flow at asubstantial velocity under conditions of viscous flow transversely of the entire face of a spinneret and extruding the filament-forming material through orifices in the spinneret face directly into the stream substantially at right angles to the general direction of the stream, thendefiecting the entire body? of the'liquid coagulating stream into a straight channel in approximatealignment' with the spin: neret orifices. and passing the filaments through the deflected stream at a controlled velocity relative to that or the stream, the velocity'of the coagulating stream transverse" of the spinneret face being, less than its velocity through a the channel.

3. The method of spinning artificial filaments comprising the step of forcing a stream of coagulating liquid to flow through a definite, confined, relatively narrow channel at a substantial velocity under conditions of viscous flow trans versely of the entire face of a spinneret and ex truding the filament-forming material through orifices in the spinneret face directly into the stream substantially at right angles to the general direction of the stream, then deflecting the entire body of the liquid coagulating stream through a definite, confined, relatively narrow, straight channel in approximate alignment with the spinneret orifices, and passing the filaments ulating liquid to flow at a substantial velocity under. conditions of viscous flow transversely of the entire face of a spinneret and extruding the filament-formingmaterial through orifices in the spinneret face directly into the stream substantially at right angles to the general direction of thestream, then deflecting the-entire body of the liquid coagulating stream through a straight channel in approximate alignment with the spinneret :ori-fices, and passing the filaments through the deflected stream at a controlled yelocityrelative; to that of, the stream, 'saidvelocity being greater than that of the stream.

5; The method of spinning, artificial filaments comprising the steps of .forcinga stream of coaguiating liquid to how at asubstantiakvelocity under condition of-viscous flow transversely of the entire face of aspinneret and extruding the filament-forming material throughorificesrin the spinneret. face directly. into the stream substantially at. right angles to theageneralzidirection of the stream, then deflecting the entire body of the@liquidcoagulating stream into a straight channel inlapproximatealignment with the spinneret orifices,- and passing the filaments; through the deflectedzstream ata controlled velocity relative to that ofuthe, stream, said velocity being the same as that of the'stream.

6..-The method of spinning artificial filaments comprising the steps of forcing astream ofcoagulating liquid to flow at a substantial velocity undenccnditionsof viscous flow'transversely. of the entire face of a spinneretand extruding the filament-forming material through orifices. in the spinneret face-directly into thez-stream. substantially atright an les to the general direction of the stream, then" deflecting the entirebodv of the -liquid coagulating stream into a straight channel in approximate alignment with. thespinneret orifices, and passing the filaments throu h the deflected stream at a controlled velocityrelative to" that of the stream; said velocity. being less than that ofthe stream.

7*. Apparatus for spinning artificialfilaments comprising aacontainer for a coagulating liquid, aspinneret in the container, a plurality of orifices in the. face of the spinneret, means forpintroducing: coagulating; liquid .into the container, said means-comprising a conduit having its discharge outlet disposed adjacent to one side only ofthe spinneret. and. to:.direct a-stream. of theliquid transversely of the entire face'ofthe spinneret, deflecting means disposed laterally of the spinneretaopposite. the position of introduction of the liquid to-the zone. in front of the spinneret,:and a straight conduit having its channel i-napproxk mate alignment; with. the spinneret face.

3. Apparatus for spinning-artificial filaments comprising a: container for a. coagulating liquid, a spinneret in the container, a plurality of orifices in the face of the spinneret, and means for introducing coagulating liquid into the container, said means comprising a conduit having its discharge outlet disposed adjacent to one side only of the spinneret and to direct a stream of the liquid transversely of the entire face of the spinneret, and a discharge conduit in alignment with the spinneret having an entrance opening to receive the stream of coagulating liquid containing the filaments, the walls of the container extending from the outlet of the first-mentioned conduit to the'entrance opening of the discharge conduit and being streamlined therebetween for continuously directing the entire body of the liquid stream entering the container through the discharge conduit.

9. Apparatus for spinning artificial filaments comprising a container for a coagulating liquid, a spinneret in the container, a plurality of orifices in the face of the spinneret, and means for introducing coagulating liquid into the container, said means comprising a conduit having its discharge outlet disposed adjacent to one side only of the spinneret and to direct a stream of the liquid transversely of the entire face of the spinneret, a discharge conduit in alignment with the spinneret, and a confining chamber communicating with said conduits having its cross-section gradually merging into that of the discharge conduit.

10. Apparatus for spinning artificial filamentscomprising a container for a coagulating liquid, a spinneret in the container, a plurality of orifices in the face of the spinneret, and means for introducing coagulating liquid into the container, said means comprising a conduit having its discharge outlet disposed adjacent to one side only of the spinneret and to direct a stream of the liquid transversely of the entire face of the spinneret, a discharge conduit in alignment with the spinneret, said discharge conduit having smaller cross-section than the first-mentioned conduit, and a confining chamber having one end about the spinneret face communicating with the firstmentioned conduit and the other end opposite the spinneret face communicating with the discharge conduit.

11. Apparatus for spinning artificial filaments comprising a container for a coagulating liquid, a spinneret in the container, a plurality of orifices in the face of the spinneret, and means for introducing coagulating liquid into the container, said means comprising a conduit having its discharge outlet disposed adjacent to one side only of the spinneret and to direct a stream of the liquid transversely of the entire face of the spinneret, a discharge conduit in alignment with the spinneret, said discharge conduit having smaller cross-section than the first-mentioned conduit, and a confining chamber having one end about the spinneret face communicating with the firstmentioned conduit and the other end opposite the spinneret face communicating with the discharge conduit, said confining chamber having its wall gradually sloped to merge with the conduits.

12. Apparatus for spinning artificial filaments comprising a container for a coagulating liquid, a spinneret in the container, a plurality of orifices in the face of the spinneret, and means for introducing coagulating liquid into the container, said means comprising a conduit having its discharge outlet disposed adjacent to one side only of the spinneret and to direct a stream of the liquid transversely of the entire face of the spinneret, a discharge conduit in alignment with the spinneret, said discharge conduit having smaller cross-section than the first-mentioned conduit, and a confining chamber having one end about, the spinneret face communicating with the first-"- mentioned conduit and the other end opposite the spinneret face communicating with the dis charge conduit, said confining chamber having its wall gradually sloped to merge with the con-- duits, the cross-section of the chamber graduallyreducing in size from a maximum near the spinneret to a minimum at its end opposite the spinneret.

13. A coagulating device for spinning artificial filaments comprising a block having a recess in; one side thereof, a plug fitting in the recess, saidplug being cut away from its innermost wall t'oi provide a chamber extending completely through the recess between opposite end walls thereof when the plug is inserted, bores through the opposite end walls of the block communicating withthe chamber, means for holding a spinneret in' one of said bores, a discharge tube secured in'the' other bore, and a conduit through the block open' ing into the recess adjacent the spinneret for directing a liquid laterally into the end of the cham'-' ber adjacent the spinneret and transversely o the spinneret face. I 14. A coagulating device for spinning artificial filaments comprising a block having a recess in one side thereof, a plug fitting in the recess, said plug being cut away from its innermost wall to provide a. chamber extending completely through the re-. cess between opposite end walls thereof when the plug is inserted, generally aligned bores through the opposite end walls of the block communicating with the chamber, means for holding a spinneret in one of said bores, a discharge tube secured in the other bore, and a conduit through the block opening into the recess adjacent the spinneret for directing a liquid laterally into the end of the chamber adjacent the spinneret and transversely of the spinneret face, the block and" plug being made of transparent materials. 1 INGHAM S. ROBERTS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,676,334 Kempf July 10, 1928 2,193,316 Feikes Mar. 12, x1940 2,241,304 Heywood et a1 May 6, 1941 FOREIGN PATENTS Number Country Date 431,681 France Nov. 16, 1911 654,817- France Apr. 11, 1929- 394,049 Great Britain June 22, 1933 822,868 France Jan. 10, 1938 

7. APPARATUS FOR SPINNING ARTIFICIAL FILAMENTS COMPRISING A CONTAINER FOR A COAGULATING LIQUID, A SPINNERET IN THE CONTAINER, A PLURALITY OF ORIFICES IN THE FACE OF THE SPINNERET, MEANS FOR INTRODUCING COAGULATING LIQUID INTO THE CONTAINER, SAID MEANS COMPRISING A CONDUIT HAVING ITS DISCHARGE OUTLET DISPOSED ADJACENT TO ONE SIDE ONLY OF THE SPINNERET AND TO DIRECT A STREAM OF THE LIQUID TRANSVERSELY TO THE ENTIRE FACE OF THE SPINNERET, DEFLECTING MEANS DISPOSED LATERALLY TO THE SPINNERET OPPOSITE THE POSITION OF INTRODUCTION OF THE LIQUID TO THE ZONE IN FRONT OF THE SPINNERET, AND A STRAIGHT CONDUIT HAVING ITS CHANNEL IN APPROXIMATE ALIGNMENT WIH THE SPINNERET FACE. 